Substrate processing apparatus with a processing chamber, transfer chamber, intermediate holding chamber, and an atmospheric pressure section

ABSTRACT

A substrate processing apparatus comprises a substrate transfer chamber; a substrate processing chamber disposed on a first side wall of the substrate transfer chamber; an intermediate substrate holding chamber disposed on a second side wall of the substrate transfer chamber; a first substrate holder disposed within the intermediate substrate holding chamber; a second substrate holder disposed within the substrate processing chamber; a first substrate transfer robot, disposed within the substrate transfer chamber, for transferring the substrate between the substrate processing chamber and the intermediate substrate holding chamber; a first gate valve disposed between the substrate processing chamber and the substrate transfer chamber; a second gate valve disposed between the substrate transfer chamber and the intermediate substrate holding chamber; an atmospheric pressure section located opposite to the substrate transfer chamber with respect to the intermediate substrate holding chamber; a third valve disposed between the intermediate substrate holding chamber and the atmospheric pressure section; a cassette holder disposed within the atmospheric pressure section; and a second substrate transfer robot disposed within the atmospheric pressure section, for transferring the substrate between a cassette held in the cassette holder and the intermediate substrate holding chamber.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a substrate processing apparatus, andparticularly to a semiconductor wafer processing apparatus.

2. Description of the Related Art

FIG. 1 is a perspective view for explaining a conventional semiconductorwafer processing apparatus, and FIG. 2 is a cross-sectional view forexplaining the conventional semiconductor wafer processing apparatus.

This conventional semiconductor wafer processing apparatus is composedof a wafer transfer chamber 150, which has a hexagonal shape as viewedfrom above, cassette chambers 131 and 132, wafer cooling chambers 141and 142, and reaction chambers 171 and 172. The cassette chambers 131and 132, the wafer cooling chambers 141 and 142, and the reactionchambers 171 and 172 are disposed on the side walls of the wafertransfer chamber 150. The wafer transfer chamber 150 is provided with awafer transfer robot 160, an arm 166 of which is located within thewafer transfer chamber 150. The cassette chamber 131 (132) has acassette elevator 129, which hoists and lowers a cassette 110 disposedwithin the cassette chamber 131 (132). The cassette 110 is loaded with aplurality of wafers 105 arranged vertically in layers. A gate valve 193is disposed between the reaction chamber 171 (172) and the wafertransfer chamber 150; a gate valve 192 is disposed between the wafertransfer chamber 150 and the cassette chamber 131 (132); and thecassette chamber 131 (132) is also provided with a front door valve 191for carrying in/out a cassette.

This conventional semiconductor wafer processing apparatus performs thefollowing series of operations: the cassette 110 loaded with a pluralityof wafers 105 is carried into the cassette chamber 131 (132) through thefront door valve 191; the cassette 110 is then lifted or lowered to apredetermined height by the cassette elevator 129 within the cassettechamber 131 (132); a wafer 105 is then transferred by the arm 166 of thewafer transfer robot 160, from the cassette 110 located within thecassette chamber 131 (132) to the reaction chamber 171 (172); the wafer105 then undergoes a predetermined processing, such as film deposition,in a heated state within the reaction chamber 171 (172); the processedwafer 105 is then transferred by the arm 166 of the wafer transfer robot160 to the wafer cooling chamber 141 (142), where the wafer 105 iscooled to a predetermined temperature; and the cooled wafer 105 is thentransferred into the cassette 110 by the arm 166 of the wafer transferrobot 160.

As described above, in the conventional semiconductor wafer processingapparatus, since the cassette 110 cannot hold a high-temperature wafer105, a processed wafer 105 is first transferred from the reactionchamber 171 (172) to the wafer cooling chamber 141 (142) so as to becooled to a predetermined temperature, and then the cooled wafer 105 istransferred to the cassette 110. Accordingly, the wafer cooling chamber141 (142) must be provided in addition to the cassette chamber 131(132).

However, the presence of the wafer cooling chamber 141 (142) increasesthe area occupied by the semiconductor wafer processing apparatus withina clean room accordingly. Further, the number of sides of the wafertransfer chamber 150 increases accordingly, resulting in an increase inthe area occupied by the wafer transfer chamber 150. This also increasesthe area occupied by the semiconductor wafer processing apparatus withinthe clean room, resulting in an increased running cost.

SUMMARY OF THE INVENTION

In view of the foregoing, the primary object of the present invention isto provide a substrate processing apparatus which occupies a relativelysmall area.

According to the present invention, there is provided a substrateprocessing apparatus comprising:

a substrate transfer chamber which can be depressurized;

a substrate processing chamber, disposed on a first side wall of thesubstrate transfer chamber, for processing a substrate;

an intermediate substrate holding chamber which is disposed on a secondside wall of the substrate transfer chamber and which can bedepressurized independently of the substrate transfer chamber;

first substrate holding means, disposed within the intermediatesubstrate holding chamber, for holding the substrate;

second substrate holding means, disposed within the substrate processingchamber, for holding the substrate;

first substrate transfer means disposed within the substrate transferchamber, the first substrate transfer means being capable oftransferring the substrate between the substrate processing chamber andthe intermediate substrate holding chamber;

a first valve, disposed between the substrate processing chamber and thesubstrate transfer chamber, the first valve being capable of providinghermetic vacuum isolation between the substrate processing chamber andthe substrate transfer chamber when closed and allowing the substrate topass therethrough when opened;

a second valve disposed between the substrate transfer chamber and theintermediate substrate holding chamber, the second valve being capableof providing hermetic vacuum isolation between the substrate transferchamber and the intermediate substrate holding chamber when closed andallowing the substrate to pass therethrough when opened;

an atmospheric pressure section located at a side which is differentfrom the substrate transfer chamber's side with respect to theintermediate substrate holding chamber;

a third valve disposed between the intermediate substrate holdingchamber and the atmospheric pressure section, said third valve beingcapable of maintaining the intermediate substrate holding chamber undervacuum in isolation from the atmospheric pressure section when closedand allowing the substrate to pass therethrough when opened;

cassette holding means disposed within the atmospheric pressure section;and

second substrate transfer means disposed within the atmospheric pressuresection, said second substrate transfer means being capable oftransferring the substrate between a cassette held in the cassetteholding means and the intermediate substrate holding chamber.

In the present invention, the intermediate substrate holding chamber isdisposed on a side wall of the substrate transfer chamber. Therefore, byusing a heat resistant substrate holder or the like as the firstsubstrate holding means disposed within the intermediate substrateholding chamber, the intermediate substrate holding chamber can be usedas a substrate cooling chamber for cooling a high-temperature substratewhich has been processed in the substrate processing chamber.

Further, since the intermediate substrate holding chamber can be used asa chamber for temporarily accommodating a substrate on the transfer pathfrom a cassette to the substrate processing chamber, for temporarilyaccommodating a substrate on the transfer path from the substrateprocessing chamber to a cassette, or for temporarily accommodating botha substrate on the transfer path from a cassette to the substrateprocessing chamber and a substrate on the transfer path from thesubstrate processing chamber to a cassette, there is no need forproviding a cassette chamber on a side wall of the substrate transferchamber. As a result, the number of chambers to be disposed on sidewalls of the substrate transfer chamber is reduced, and the areaoccupied by the substrate processing apparatus within a clean room canbe reduced accordingly. Further, the number of sides of the wafertransfer chamber is reduced, and the size of the substrate transferchamber is reduced accordingly, resulting in a decrease in the areaoccupied by the substrate transfer chamber. This also reduces the areaoccupied by the substrate processing apparatus within the clean room.

As the number of sides of the substrate transfer chamber is reduced, thecost of manufacture of the substrate transfer chamber is reduced. As thenumber of sides increases, the required multidirectional maintenancespace increases accordingly. By contrast, according to the presentinvention, the number of sides of the substrate transfer chamber can bereduced, and the required multidirectional maintenance space can bereduced accordingly. Further, a reduction in the number of sides of thesubstrate transfer chamber decreases the distance over which aconnection is made between the substrate transfer chamber and anothersubstrate transfer chamber or the like. As a result, a substrate can betransferred between the substrate transfer chamber and another substratetransfer chamber or the like without providing a substrate transferdevice at a connecting section therebetween; thus the substrateprocessing apparatus can be made simpler in structure and manufacturedat lower cost accordingly.

Since the substrate transfer chamber and the intermediate substrateholding chamber can be depressurized, the oxygen concentration thereincan be reduced to a minimal level, thereby suppressing oxidation of asubstrate in the substrate transfer chamber and the intermediatesubstrate holding chamber.

The second valve is disposed between the substrate transfer chamber andthe intermediate substrate holding chamber, and the second valve iscapable of providing hermetic vacuum isolation between the substratetransfer chamber and the intermediate substrate holding chamber whenclosed and allowing a substrate to pass therethrough when opened.Therefore, the substrate transfer chamber and the intermediate substrateholding chamber can be maintained under vacuum independently of eachother, and also a substrate can move between the substrate transferchamber and the intermediate substrate holding chamber. This secondvalve is preferably a gate valve.

Further, the third valve is preferably disposed between the intermediatesubstrate holding chamber and the atmospheric pressure section, and thethird valve is capable of maintaining the intermediate substrate holdingchamber under vacuum in isolation from the atmospheric pressure sectionwhen closed and allowing a substrate to pass therethrough when opened.Therefore, the intermediate substrate holding chamber can be maintainedunder vacuum in isolation from the atmospheric pressure section, andalso a substrate can move between the intermediate substrate holdingchamber and the atmospheric pressure section.

As described above, since the second and third valves are disposed atthe intermediate substrate holding chamber and the intermediatesubstrate holding chamber can be depressurized independently of thesubstrate transfer chamber, the intermediate substrate holding chambercan function as a load-lock chamber when a substrate is transferredbetween the atmospheric pressure section and the substrate transferchamber maintained under reduced pressure.

As described above, since the intermediate substrate holding chamber canbe used as a substrate cooling chamber as well as a load-lock chamber,it is not necessary to provide a substrate cooling chamber and acassette chamber on side walls of the substrate transfer chamber, and acassette can be placed within the atmospheric pressure chamber.

Since the second valve is disposed between the substrate transferchamber and the intermediate substrate holding chamber, the pressure ofthe intermediate substrate holding chamber can be restored toatmospheric pressure while the substrate transfer chamber is maintainedunder reduced pressure; and a substrate contained in the intermediatesubstrate holding chamber naturally cools down while the pressure of theintermediate substrate holding chamber is being restored to atmosphericpressure, so that the temperature of the substrate can be lowered to asufficient level before the substrate leaves the intermediate substrateholding chamber. Consequently, when the substrate is subsequently takenout into atmospheric environment, it can be prevented from beingoxidized or contaminated by atmospheric environment. In this manner, astep of restoring pressure to atmospheric pressure and a step of coolinga substrate can be simultaneously performed within the intermediatesubstrate holding chamber, and subsequently the cooled substrate can betransferred under atmospheric pressure to a cassette. A cassette whichcontains substrates can then be taken out from the substrate processingapparatus.

Conventionally, since a cassette chamber and a cooling chamber aredisposed on side walls of the substrate transfer chamber, the firstsubstrate transfer means disposed within the substrate transfer chambermust also be used for transferring a substrate between the cassettechamber and the cooling chamber. By contrast, in the present invention,the second substrate transfer means, not the first substrate transfermeans disposed within the substrate transfer chamber, can be used fortransferring a substrate between the intermediate substrate holdingchamber and a cassette, thereby reducing time required for transferringa substrate. Also, in the present invention, within the atmosphericpressure section are disposed the cassette holding means and the secondsubstrate transfer means capable of transferring a substrate between acassette held by the cassette holding means and the intermediatesubstrate holding chamber. Thus, the cassette holding means and thesecond substrate transfer means can be made simpler in structure ascompared with the case where they are disposed in a vacuum environment.

A cassette is preferably a cassette for carrying substrates into and/orcarrying them out from the substrate processing apparatus.

Further, the first valve is disposed between the substrate processingchamber and the substrate transfer chamber, and the first valve iscapable of providing hermetic vacuum isolation between the substrateprocessing chamber and the substrate transfer chamber when closed andallowing a substrate to pass therethrough when opened. Therefore, thesubstrate processing chamber and the substrate transfer chamber can bemaintained under vacuum independently of each other, and also asubstrate can move between the substrate processing chamber and thesubstrate transfer chamber. This first valve is preferably a gate valve.

A substrate is preferably a semiconductor wafer. In this case, thesubstrate processing apparatus functions as a semiconductor waferprocessing apparatus.

A substrate may also be a glass substrate for use in a liquid crystaldisplay device.

In the substrate processing chamber, there are preferably performedprocesses including: the deposition of various films, includinginsulating films, metal wiring films, polycrystalline silicon films, andamorphous silicon films, by various CVD (Chemical Vapor Deposition)methods such as a plasma enhanced CVD method, a hot wall CVD method, aphoto-assisted CVD method, and the like; etching; heat treatment such asannealing and the like; epitaxial growth; and diffusion.

Preferably, heat resistant substrate holding means is disposed withinthe intermediate substrate holding chamber, whereby the intermediatesubstrate holding chamber can be used as a substrate cooling chamber forcooling a high-temperature substrate which has been processed in thesubstrate processing chamber.

Preferably, a heat resistant substrate holding device made of quartz,glass, ceramics, or metal is disposed within the intermediate substrateholding chamber, whereby the intermediate substrate holding chamber canbe used as a substrate cooling chamber for cooling a high-temperaturesubstrate which has been processed in the substrate processing chamberand whereby even when the intermediate substrate holding chamber ismaintained under vacuum, impurities are not outgassed from the substrateholding device, thereby maintaining clean the atmosphere within theintermediate substrate holding chamber. Ceramics are preferably sinteredSiC, or sintered SiC coated with SiO₂ by CVD or the like.

Preferably, the substrate processing chamber, the substrate transferchamber, and the intermediate substrate holding chamber can bedepressurized independently of one another. This allows the following: asubstrate can be prevented from oxidizing within the substrate transferchamber and the intermediate substrate holding chamber; the intermediatesubstrate holding chamber can be used not only as a load-lock chamberbut also as a substrate processing chamber for processing a substrateunder reduced pressure; and after the substrate processing chamber isdepressurized, the atmosphere therein can be replaced with apredetermined atmospheric gas, thereby establishing a highly puregaseous atmosphere therein.

Preferably, the substrate processing chamber is a substrate processingchamber for processing a substrate under reduced pressure.

The substrate processing chamber may be a substrate processing chamberfor processing a substrate under atmospheric pressure.

Preferably, a plurality of substrate processing chambers for processinga substrate, are disposed such that they are stacked in the verticaldirection on the first side wall of the substrate transfer chamber. Thisreduces the area occupied by the substrate processing chambers within aclean room. Also, the number of sides of the substrate transfer chambercan be reduced thereby to reduce the size of the substrate transferchamber, resulting in a reduction in the area occupied by the substratetransfer chamber. Thus, the substrate processing apparatus occupies lessarea within the clean room.

As the number of sides of the substrate transfer chamber is reduced, thecost of manufacture of the substrate transfer chamber is reduced, andthe required multidirectional maintenance space is also reduced.Further, the distance over which a connection is made between thesubstrate transfer chamber and another substrate transfer chamber or thelike can also be reduced. This allows a substrate to be transferredbetween the substrate transfer chamber and another substrate transferchamber or the like without providing a substrate transfer device at aconnecting section therebetween; thus the substrate processing apparatuscan accordingly be made simpler in structure and manufactured at lowercost.

Preferably, these substrate processing chambers are all used forprocessing a substrate under reduced pressure.

As another preferable way, at least one of these substrate processingchambers may be used for processing a substrate under atmosphericpressure, and the remaining substrate processing chambers may be usedfor processing a substrate under reduced pressure.

The first substrate transfer means is preferably a substrate transferdevice for transferring a substrate in a horizontal direction, morepreferably an articulated robot.

Preferably, an elevator is disposed which can hoist and lower the firstsubstrate transfer means. The elevator is disposed preferably outsidethe substrate transfer chamber so as to not contaminate the atmospherewithin the substrate transfer chamber.

Preferably, the second substrate holding means can hold a plurality ofsubstrates, the first substrate holding means can hold a plurality ofsubstrates, and the pitch of substrates held by the first substrateholding means is substantially identical to that of substrates held bythe second substrate holding means.

In this case, since the second substrate holding means disposed withinthe substrate processing chamber can hold a plurality of substrates, thesubstrate processing efficiency of the substrate processing chamber canbe increased.

In this case, since the first substrate holding means disposed withinthe intermediate substrate holding chamber can hold a plurality ofsubstrates and the pitch of substrates held by the first substrateholding means is substantially identical to that of substrates held bythe second substrate holding means, the structure of the first substratetransfer means disposed within the substrate transfer chamber can besimplified. Preferably, the first substrate transfer means can transfera plurality of substrates at one time under reduced pressure.

In the case where the pitch of substrates held by the first substrateholding means is made substantially identical to that of substrates heldby the second substrate holding means, there is no need for changing thepitch of substrates while transferring substrates, even when the firstsubstrate transfer means adopts the structure capable of transferring aplurality of substrates at one time under reduced pressure. As a result,the structure of the first substrate transfer means becomes simple, andcontamination of vacuum can be prevented. Further, since a plurality ofsubstrates can be transferred at one time, the efficiency oftransferring substrates increases.

By contrast, if the pitch of substrates is made variable on the transferpath under reduced pressure, the structure of transfer means will becomecomplicated, and more than twice as much cost and space will be requiredas compared with the use of the transfer means under atmosphericpressure. Moreover, due to an increase in the number of mechanisms,contaminants generated from a driving shaft and the like become morelikely to scatter.

This results in a failure to maintain a predetermined degree of vacuumand is likely to introduce a problem of particles and to causecontamination of a substrate. Since particles are generated, within thesubstrate transfer chamber, adjacent to the substrate processingchamber, the effect of particles is particularly large. If in order toavoid such a problem, substrates are transferred one by one between thefirst substrate holding means and the second substrate holding means,throughput will deteriorate. If in order to improve throughput, thetransferring speed of a substrate transfer robot is increased, thenumber of operations per unit time of the substrate transfer robot willincrease, resulting in a decrease in service life of the apparatus andintroduction of a problem of particles.

In order to concurrently process, for example, to concurrently deposit afilm on a plurality of substrates within the substrate processingchamber, these substrates must be arranged not at the pitch of groovesin a cassette, but at a pitch which is determined in consideration of agas flow and the like within the substrate processing chamber, so as tomaintain uniformity of a film thickness and the like. Therefore, it ispreferable that the pitch of substrates be changed from the pitch of thegrooves in the cassette at a certain point of transfer of substrates.

In the present invention, the second substrate transfer means preferablyhas a structure capable of transferring a plurality of substrates at onetime and changing the pitch of these substrates. Since the secondsubstrate transfer means is used under atmospheric pressure, even whenthe pitch of substrates can be made changeable, the second substratetransfer means is simpler in structure and can be manufactured at lowercost as compared with that for use under vacuum, and the generation ofparticles can be suppressed.

By adopting the above-mentioned method of transferring a plurality ofsubstrates at one time while the pitch of substrates is variable duringtransfer under atmospheric pressure and fixed during transfer underreduced pressure, the cost of manufacture of transfer devices can bereduced, the size of the transfer devices can be reduced, and thegeneration of particles can be suppressed so as to provide a cleanenvironment for transfer of substrates. Further, since a plurality ofsubstrates are transferred at one time, throughput improves. Since thepitch of substrates is variable, the pitch can be changed so as toprocess substrates at high precision within the substrate processingchamber.

A plurality of intermediate substrate holding chambers may be disposedon a side wall of the substrate transfer chamber, whereby while acertain intermediate substrate holding chamber is used for cooling asubstrate contained therein, another intermediate substrate holdingchamber may be used for transferring a substrate to the substrateprocessing chamber, thereby saving time.

Preferably, a plurality of intermediate substrate holding chambers aredisposed such that they are stacked in the vertical direction on thesecond side wall of the substrate transfer chamber. This reduces thearea occupied by the intermediate substrate holding chambers within aclean room. Also, the number of sides of the substrate transfer chambercan be reduced to thereby reduce the size of the substrate transferchamber, resulting in a reduction in the area occupied by the substratetransfer chamber. Thus, the substrate processing apparatus occupies lessarea within the clean room.

As the number of sides of the substrate transfer chamber is reduced, thecost of manufacture of the substrate transfer chamber is reduced, andthe required multidirectional maintenance space is also reduced.Further, when a plurality of substrate processing apparatuses aredisposed, the distance over which a connection is made between thesubstrate transfer chamber and another substrate transfer chamber or thelike can be reduced. This allows a substrate to be transferred betweenthe substrate transfer chamber and another substrate transfer chamber orthe like without providing a substrate transfer device at a connectingsection therebetween; thus the substrate processing apparatus canaccordingly be made simpler in structure and manufactured at lower cost.Further, the maintenance space for one substrate processing apparatusdoes not interfere with that for another substrate processing apparatus;therefore a plurality of substrate processing apparatuses can beefficiently arranged.

Two kinds of intermediate substrate holding chambers, one for incomingsubstrates and the other for outgoing substrates, may be separatelydisposed. This allows two kinds of intermediate substrate holdingchambers to be alternately used, thereby saving time.

Preferably, the first substrate holding means can hold at least twice asmany substrates as those to be processed at one time within each of thesubstrate processing chambers.

Preferably, the first substrate holding means can hold at least twice asmany substrates as those to be held by the second substrate holdingmeans, whereby the first substrate holding means can hold at least twiceas many substrates as those to be processed at one time within each ofthe substrate processing chambers.

As a result, substrates can be efficiently transferred between thesubstrate processing chamber and a cassette, thereby improvingthroughput.

Preferably, the first and second side walls of the substrate transferchamber are opposed to each other so as to arrange on a substantiallystraight line the substrate processing chamber, the substrate transferchamber, and the intermediate substrate holding chamber. This minimizesthe number of sides of the substrate transfer chamber; for example, thesubstrate transfer chamber may assume a rectangular shape.

Preferably, the substrate transfer chamber has a rectangular shape asviewed from above, thereby reducing the size of the substrate transferchamber and thus reducing the area occupied by the substrate transferchamber. Thus, the substrate processing apparatus occupies less areawithin a clean room. By adopting the rectangular shape, the cost ofmanufacture of the substrate transfer chamber is reduced, and a requiredmaintenance space is also reduced. Further, the distance over which aconnection is made between the substrate transfer chamber and anothersubstrate transfer chamber or the like can be reduced. This allows asubstrate to be readily transferred between the substrate transferchamber and another substrate transfer chamber or the like withoutproviding a substrate transfer device at a connecting sectiontherebetween; thus the substrate processing apparatus can accordingly bemade simpler in structure and manufactured at lower cost. A plurality ofsubstrate processing units, each comprising the structure such that thesubstrate processing chamber, the substrate transfer chamber, and theintermediate substrate holding chamber are arranged on a substantiallystraight line, can be readily arranged in parallel so that they occupyless area.

Preferably, the cassette holding means is located opposite to thesubstrate transfer chamber with respect to the intermediate substrateholding chamber.

Preferably, the second substrate transfer means is disposed between theintermediate substrate holding chamber and the cassette holding means.The second substrate transfer means is preferably cassette transfer andsubstrate transfer means capable of transferring the substrate betweenthe cassette held by the cassette holding means and the intermediatesubstrate holding chamber, as well as capable of transferring thecassette to and from the cassette holding means.

The first substrate holding means preferably has a substrate supportinggroove which is open-ended in the front and rear directions of the firstsubstrate holding means so as to carry in a substrate from either thefront or rear side of the first substrate holding means, as well as totake out a substrate from either the front or rear side of the firstsubstrate holding means.

Preferably, a housing is disposed for accommodating the substrateprocessing chamber, the substrate transfer chamber, the intermediatesubstrate holding chamber, the second substrate transfer means, and thecassette holding means. By disposing the second substrate transfer meansand the cassette holding means within the housing, the surface of asubstrate placed in a cassette and the surface of a substrate beingtransferred by the second substrate transfer means can be maintainedclean.

Preferably, a cassette stage is disposed under the cassette holdingmeans within the housing, for holding a cassette which has been carriedinto the housing, for holding a cassette to be carried out from thehousing, or for holding a cassette which has been carried into thehousing as well as holding a cassette to be carried out from thehousing. Therefore, the substrate in the cassette held by the cassetteholding means is prevented from being affected by particles which enterthe housing from outside while a cassette is being transferred to thecassette stage or which enter the housing from outside through acassette IN/OUT opening through which a cassette enters/leaves thehousing.

Preferably, the cassette transfer and substrate transfer means ismounted on the elevator so as to transfer a cassette between thecassette stage and the cassette holding means.

Preferably, there are provided a plurality of substrate processingunits, each comprising the substrate processing chamber, the substratetransfer chamber, the first substrate transfer means, and theintermediate substrate holding chamber; and these substrate processingunits are interconnected via a second intermediate substrate transferchambers each disposed between adjacent substrate transfer chambers.

In the above-mentioned plurality of substrate processing units which areinterconnected via second intermediate substrate transfer chambers eachdisposed between adjacent substrate transfer chambers, the substratetransfer chambers preferably have a rectangular shape as viewed fromabove. In this case, since the distance between adjacent substratetransfer chambers can be made relatively short, there is no need forproviding a substrate transfer device in each of the second intermediatesubstrate transfer chambers.

According to the present invention, there is also provided a substrateprocessing apparatus, comprising a substrate transfer chamber;

a plurality of substrate processing chamber disposed on a side wall ofthe substrate transfer chamber, the plurality of substrate processingchamber being stacked in the vertical direction and being seperated byone another.

Preferably, the substrate transfer chamber is a chamber for transferringa substrate under a vacuum condition.

Preferably, this substrate processing apparatus further comprises aplurality of gate valves respectively disposed between the plurality ofsubstrate processing chambers and the substrate transfer chamber.

Still preferably, the substrate processing apparatus further comprises aplurality of substrate holding chambers disposed on a second side wallof the substrate transfer chamber, the plurality of substrate holdingchambers being stacked in the vertical direction and being separated byone another; and

a plurality of second gate valves respectively disposed between theplurality of substrate holding chambers and the substrate transferchamber.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and further objects, features and advantages of the presentinvention will become more apparent from the following detaileddescription taken in conjunction with the accompanying drawings,wherein:

FIG. 1 is a perspective view for explaining a conventional semiconductorwafer processing apparatus;

FIG. 2 is a cross-sectional view for explaining the conventionalsemiconductor wafer processing apparatus;

FIG. 3 is a plan view for explaining a semiconductor wafer processingapparatus according to a first embodiment of the present invention;

FIG. 4 is a cross-sectional view taken along the line X--X in FIG. 3;

FIG. 5 is a schematic perspective view for explaining a wafer holder foruse in the first through seventh embodiments of the present invention;

FIGS. 6A and 6B are schematic perspective views for explaining awafer-transfer vacuum robot for use in the first through seventhembodiments of the present invention;

FIG. 7 is a schematic perspective view for explaining a cassettetransfer and wafer transfer device for use in the first through seventhembodiments of the present invention;

FIG. 8A is a side view for explaining a pitch changing mechanism of thecassette transfer and wafer transfer device for use in the first throughseventh embodiments of the present invention;

FIG. 8B is a rear view taken along the line Y--Y in FIG. BA;

FIG. 9 is a schematic cross-sectional view for explaining the operationof transferring wafers in the semiconductor processing apparatusaccording to the first embodiment;

FIG. 10 is a cross-sectional view for explaining a semiconductor waferprocessing apparatus according to a second embodiment of the presentinvention;

FIG. 11 is a cross-sectional view for explaining a semiconductor waferprocessing apparatus according to a third embodiment of the presentinvention;

FIG. 12 is a plan view for explaining a semiconductor wafer processingapparatus according to a fourth embodiment of the present invention;

FIG. 13 is a plan view for explaining a semiconductor wafer processingapparatus according to a fifth embodiment of the present invention;

FIG. 14 is a plan view for explaining a semiconductor wafer processingapparatus according to a sixth embodiment of the present invention; and

FIG. 15 is a plan view for explaining a semiconductor wafer processingapparatus according to a seventh embodiment of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS First Embodiment

FIG. 3 is a plan view for explaining a semiconductor wafer processingapparatus according to a first embodiment of the present invention. FIG.4 shows a cross-sectional view taken along the line X--X in FIG. 3.

A semiconductor wafer processing apparatus 1 of the present embodimentis composed of a processing section 700, a transfer section 500, and afront section 100.

The processing section 700 is composed of a plurality of processingmodules 701, each including a reaction chamber 70 and a gate valve 93.The transfer section 500 is composed of a transfer module 501, whichincludes a wafer transfer chamber 50 and a wafer-transfer vacuum robot60. The front section 100 is composed of a plurality of load-lockmodules 300 and an atmospheric pressure section 200. Each load-lockmodule 300 is composed of an intermediate wafer holding chamber 30, agate valve 92, and a front door valve 91. In the atmospheric pressuresection 200, there are disposed cassette shelves 11, each being used formounting a cassette 10 thereon, and a cassette transfer and wafertransfer device 20.

The plurality of reaction chambers 70 are arranged in the verticaldirection and connected to a wall 53 of the wafer transfer chamber 50.The gate valve 93 is disposed between each reaction chamber 70 and thewafer transfer chamber 50. Each reaction chamber 70 is adapted to beindependently evacuated via an exhaust pipe 82. Within each reactionchamber 70 is placed a wafer boat 75 capable of carrying a plurality of(two in the present embodiment) semiconductor wafers 5 so as to processa plurality of wafers 5 at one time, thereby increasing the waferprocessing efficiency. The pitch of wafers 5 carried in the wafer boat75 is determined in consideration of a gas flow and the like within thereaction chamber 70; for example, when a process of depositing a film isto be performed within the reaction chamber 70, the pitch is determinedso as to maintain the uniformity of film thickness within apredetermined range.

In the reaction chamber 70 there are performed processes including: thedeposition of various films, including insulating films, metal wiringfilms, polycrystalline silicon films, and amorphous silicon films, byvarious kinds of CVD such as plasma enhanced CVD, hot wall CVD, photoassisted CVD, and the like; etching; heat treatment such as annealingand the like; epitaxial growth; diffusion.

Since the plurality of reaction chambers 70 are disposed in verticallayers on the wall 53 of the wafer transfer chamber 50, the areaoccupied by the reaction chambers 70 within a clean room can be reduced.Also, the number of sides of the wafer transfer chamber 50 can bereduced thereby to reduce the size of the wafer transfer chamber 50,resulting in a reduction in the area occupied by the wafer transferchamber 50. Thus, the semiconductor wafer processing apparatus 1occupies less area within the clean room.

As the number of sides of the wafer transfer chamber 50 is reduced, thecost of manufacture of the wafer transfer chamber 50 is reduced, and therequired multidirectional maintenance space is also reduced. Further, inthe case where another wafer transfer chamber is connected to the wafertransfer chamber 50, the distance between the wafer transfer chamber 50and another wafer transfer chamber or the like can be reduced. Thisallows a wafer to be transferred between the wafer transfer chamber 50and another wafer transfer chamber or the like without providing a wafertransfer device at a connecting section therebetween; thus thesemiconductor wafer processing apparatus 1 can accordingly be madesimpler in structure and manufactured at lower cost.

The plurality of intermediate wafer holding chambers 30 are disposed invertical layers on a wall 54 of the wafer transfer chamber 50. The gatevalve 92 is disposed between each intermediate wafer holding chamber 30and the wafer transfer chamber 50. The front door valve 91 is disposedbetween each intermediate wafer holding chamber 30 and the atmosphericpressure section 200. Each intermediate wafer holding chamber 30 isadapted to be independently evacuated via exhaust pipes 83 and 81.

A wafer holder 40 is placed within the intermediate wafer holdingchamber 30. FIG. 5 is a schematic perspective view for explaining thewafer holder 40. The wafer holder 40 has upper and lower disk-likecolumn supporting plates 41 and 42 and two prismatic columns 43 and 44,which are held between the plates 41 and 42. A plurality of wafersupporting grooves 45 are formed in each of the columns 43 and 44, andthe columns 43 and 44 stand such that respective grooves 45 face eachother. The both ends of the grooves 45 are open so as to allow wafers tobe loaded from both sides of the wafer holder 40 and to be unloaded toboth sides thereof. The wafer holder 40 is made of quartz.

The pitch of the wafer supporting grooves 45 of the wafer holder 40,i.e. the pitch of wafers 5 held in the wafer holder 40 is made equal tothat of wafers 5 mounted in the wafer boat 75 in the reaction chamber70. The pitch of the wafer supporting grooves 45 of the wafer holder 40is larger than that of grooves for holding wafers within the cassette10.

The number of the wafer supporting grooves 45 of the wafer holder 40,i.e. the number of wafers 5 which the wafer holder 40 can hold is atleast twice the number of wafers 5 which the wafer boat 7 within thereaction chamber 70 can carry, i.e. at least twice the number of wafers5 which can be processed at one time within the reaction chamber 70.Thus, the wafers 5 can be efficiently transferred between the reactionchamber 70 and the cassette 10, resulting in improved throughput.

Since the wafer holder 40 is made of quartz, even when the intermediatewafer holding chamber 30 is maintained under vacuum, impurities are notoutgassed from the wafer holder 40, thereby maintaining clean theatmosphere within the intermediate wafer holding chamber 30.

Since the wafer holder 40 is made of quartz and thus has excellent heatresistance, the high-temperature wafer 5 which has been processed in thereaction chamber 70 can be cooled while being held in the wafer holder40. The wafer holder 40 can thus be used for cooling wafers 5, so thatthe intermediate wafer holding chamber 30 functions as a wafer coolingchamber. Accordingly, there is no need for providing a separate coolingchamber on a side wall of the wafer transfer chamber 50 in order to coolthe high-temperature wafer 5 which has been processed in the reactionchamber 70, whereby the area occupied by the semiconductor waferprocessing apparatus 1 within a clean room can be reduced by the areawhich would otherwise be occupied by the cooling chamber. Also, thenumber of sides of the wafer transfer chamber 50 can be reduced therebyto reduce the size of the wafer transfer chamber 50, resulting in areduction in the area occupied by the wafer transfer chamber 50. Thus,the semiconductor wafer processing apparatus 1 occupies less area withinthe clean room. Further, the cost of manufacture of the wafer transferchamber 50 can be reduced.

Since the wafer holder 40 temporarily accommodates wafers on thetransfer path from the cassette 10 to the wafer processing chamber 70,temporarily accommodates wafers 5 on the transfer path the waferprocessing chamber 70 to the cassette 10, or temporarily accommodateswafers 5 on the transfer path from the cassette 10 to the waferprocessing chamber 70 as well as wafers 5 on the transfer path from thewafer processing chamber 70 to the cassette 10, there is no need forproviding a cassette chamber for accommodating the cassette 10 on a sidewall of the wafer transfer chamber 50. As a result, the number ofchambers to be disposed on side walls of the wall transfer chamber 50 isreduced, and the area occupied by the wafer processing apparatus 1within a clean room can be reduced accordingly. Further, the number ofsides of the wafer transfer chamber 50 is reduced, and the size of thewafer transfer chamber 50 is reduced accordingly, resulting in adecrease in the area occupied by the wafer transfer chamber 50. Thisalso reduces the area occupied by the semiconductor wafer processingapparatus 1 within the clean room. Further, the cost of manufacture ofthe wafer transfer chamber 50 is reduced.

In the present embodiment, since the plurality of intermediate waferholding chambers 30 are disposed on the wall 54 of the wafer transferchamber 50, while a certain intermediate wafer holding chamber 30 isused for cooling wafers 5, another intermediate wafer holding chamber 30may be used for transferring wafers 5 to the reaction chamber 70,thereby saving time. Also, two kinds of the intermediate wafer holdingchambers 30, one for incoming wafers 5 and the other for outgoing wafers5, may be separately provided. This allows two kinds of the intermediatewafer holding chambers 30 to be alternately used, thereby saving time.Further, a certain intermediate wafer holding chamber 30 may be used formonitor wafers, and another intermediate wafer holding chamber 30 may beused for process wafers which will become actual products.

Since the plurality of intermediate wafer holding chambers 30 aredisposed in vertical layers on the wall 54 of the wafer transfer chamber50, the area occupied by the intermediate wafer holding chambers 30within a clean room can be reduced. Also, the number of sides of thewafer transfer chamber 50 can be reduced thereby to reduce the size ofthe wafer transfer chamber 50, resulting in a reduction in the areaoccupied by the wafer transfer chamber 50. Thus, the semiconductor waferprocessing apparatus 1 occupies less area within the clean room.Further, the cost of manufacture of the wafer transfer chamber 50 isreduced.

Since the gate valve 92 is disposed between the wafer transfer chamber50 and the intermediate wafer holding chamber 30, the pressure of theintermediate wafer holding chamber 30 can be restored to atmosphericpressure while the wafer transfer chamber 50 is maintained under reducedpressure. Therefore, each wafers 5 contained in the intermediate waferholding chamber 30 cools naturally down while the pressure of theintermediate wafer holding chamber 30 is being restored to atmosphericpressure, so that the temperature of each wafer 5 is lowered to asufficient level before the wafer 5 leaves the intermediate waferholding chamber 30. Accordingly, even when the wafers 5 are subsequentlytaken out into atmospheric environment, the wafers 5 are prevented frombeing oxidized or contaminated by atmospheric environment. In thismanner, a step of restoring pressure to atmospheric pressure and a stepof cooling wafers 5 are simultaneously performed within the intermediatewafer holding chamber 30, and subsequently the cooled wafers 5 aretransferred under atmospheric pressure to the cassette 10. The cassette10 which contains the wafers 5 is then delivered out from the waferprocessing apparatus 1.

In the conventional apparatus shown in FIGS. 1 and 2, since cassettechambers 131 and 132 and cooling chambers 141 and 142 are disposed onside walls of a wafer transfer chamber 150, a wafer-transfer vacuumrobot 160 disposed within the wafer transfer chamber 150 must be usedfor transferring a wafer between the cassette chambers 131 and 132 andthe cooling chambers 141 and 142. By contrast, in the presentembodiment, the cassette transfer and wafer transfer device 20, not thewafer-transfer vacuum robot 60 disposed within the wafer transferchamber 50, is used for transferring wafers 5 between the intermediatewafer holding chamber 30 and the cassettes 10, thereby reducing timerequired for transferring wafers 5. Also, in the present embodiment,since the cassette transfer and wafer transfer device 20 is disposedwithin the atmospheric pressure section 200, the cassette transfer andwafer transfer device 20 can be made simpler in structure as comparedwith the case where it is disposed in a vacuum atmosphere.

The wafer transfer chamber 50 is adapted to be evacuated via the exhaustpipes 84 and 81. Also, the plurality of reaction chambers 70, the wafertransfer chamber 50, and the plurality of intermediate wafer holdingchambers 30 are adapted to be evacuated independently of one another.

Since the wafer transfer chamber 50 and the intermediate wafer holdingchamber 30 can be depressurized, the oxygen concentration therein can bereduced to an ultimate level, thereby suppressing oxidation of wafers 5in the wafer transfer chamber 50 and in the intermediate wafer holdingchamber 30.

Since the reaction chambers 70 can be independently evacuated, each ofthe reaction chambers 70 can function as a reaction chamber forprocessing wafers 5 under reduced pressure. Further, after the reactionchamber 70 is depressurized, the atmosphere therein can be replaced witha predetermined atmospheric gas, thereby establishing a highly puregaseous atmosphere therein.

In the present embodiment, the plurality of reaction chambers 70 are allused for processing wafers 5 under reduced pressure. However, theplurality of reaction chambers 70 may all be used for processing wafers5 under atmospheric pressure, or at least one of these reaction chambers70 may be used for processing wafers 5 under atmospheric pressure whilethe remaining reaction chambers 70 may be used for processing wafers 5under reduced pressure.

The wafer-transfer vacuum robot 60 is disposed within the wafer transferchamber 50. FIGS. 6A and 6B are schematic perspective views forexplaining the wafer-transfer vacuum robot 60. The wafer-transfer vacuumrobot 60 is an articulated robot and is composed of arms 63, 65, and 67,each swingable in a corresponding horizontal plane, and rotational axles62, 64, and 66 for swinging the respective arms. The robot 60 alsoinclude a two-axis driving unit 69 for rotating the rotational axle 62,a gear mechanism (not shown) for transmitting the rotation of therotational axle 62 to the rotational axles 64 and 66, and a driving unitcontainer 61 for accommodating the driving unit 69. The tip of the arm67 is formed into a wafer mounting arm 68 for mounting wafers 5 thereon.As the rotational axle 62 rotates, the arms 63, 65, and 67 swing in thecorresponding horizontal planes, thereby moving wafers 5 mounted thewafer mounting arm 68 in a horizontal direction.

Two sets of the arm 67 and the wafer mounting arm 68 are disposed. Thedistance between the wafer mounting arms 68 is made equal to the pitchof the wafer supporting grooves 45 of the wafer holder 40 and the pitchof wafers 5 mounted in the wafer boat 75 contained in the reactionchamber 70. Accordingly, there is no need for changing the pitch ofwafers 5 on the way of transfer between the wafer holder 40 and thereaction chamber 70. Thus, although the wafer-transfer vacuum robot 60can transfer two wafers 5 at one time using the two wafer mounting arms68, the structure of the wafer-transfer vacuum robot 60 can besimplified, and contamination of a vacuum atmosphere can be prevented.Further, since two wafers 5 can be transferred at one time, the wafertransferring efficiency increases.

The driving unit container 61 has a hermetically sealed structure. Sincethe driving unit is accommodated in this hermetically sealed container61, the atmosphere within the wafer transfer chamber 50 can bemaintained clean.

A projecting section 52 whose shape corresponds to that of the drivingunit container 61 is projected from a bottom 56 of the wafer transferchamber 50 so as to accommodate the driving unit container 61. In orderto accommodate the driving unit container 61, only the projectingsection 52 is projected from the wafer transfer chamber 50 withoutincreasing the entire size of the wafer transfer chamber 50, thereforevolume of the wafer transfer chamber 50 can be reduced, thereby reducingtime required for evacuating the wafer transfer chamber 50.

A through-hole 57 is formed in the bottom 56 of the wafer transferchamber 50. A screw shaft 561 is vertically disposed outside and underthe wafer transfer chamber 50. A motor 566 is disposed on the upperportion of the screw shaft 561 so as to rotate the screw shaft 561. Anut 565 is attached to the screw shaft 561, thereby forming a ball screwby the nut 565 and the screw shaft 561. A lifting base 564 is fixed tothe nut 565. One end of a support bar 563 for supporting thewafer-transfer vacuum robot 60 is fixed onto the lifting base 564 suchthat the support bar 563 stands upright on the lifting base 564. Anotherend of the support bar 563 is fixed to the upper end portion of thedriving unit container 61 of the wafer-transfer vacuum robot 60. Thesupport bar 563 is made of stainless steel. Metal bellows 562 isdisposed so as to cover the support bar 563 and such that one end of thebellows 562 is fixed in a hermetically sealed manner onto the bottom 56so as to surround the through-hole 57 while the other end of the bellows562 is fixed in a hermetically sealed manner onto the top surface of thelifting base 564.

As the screw shaft 561 is rotated by the motor 566, the nut 565 goes upand down, and the lifting base 564 fixed to the nut 565 goes up and downaccordingly. As the lifting base 564 goes up and down, the support bar563, which is fixed perpendicularly onto the lifting base 564, forsupporting the wafer-transfer vacuum robot 60 goes up and down, and thewafer-transfer vacuum robot 60 attached to the support bar 563 goes upand down accordingly.

The present embodiment uses the ball screw 560 composed of screw shaft561 and the nut 565, thereby reducing friction and increasing mechanicalefficiency. Since the ball screw 560 is disposed outside the wafertransfer chamber 50, the interior of the wafer transfer chamber 50 canbe prevented from being contaminated, thereby preventing wafers 5 frombeing contaminated. Further, since the ball screw 560 is located underthe bottom 56 of the wafer transfer chamber 50, the interior of thewafer transfer chamber 50 can be prevented from being contaminated withparticles generated from the bellows 562.

Since the wafer-transfer vacuum robot 60 is mechanically connected tothe lifting base 564 via the rigid stainless-steel support bar 563 forsupporting the wafer-transfer vacuum robot 60, the wafer-transfer vacuumrobot 60 goes up and down reliably as the lifting base 564 goes up anddown.

The support bar 563 for supporting the wafer-transfer vacuum robot 60 iscovered with the bellows 562 such that one end of the bellows 562 isfixed in a hermetically sealed manner onto the bottom 56 of the wafertransfer chamber 50 so as to surround the through-hole 57 while theother end of the bellows 562 is fixed in a hermetically sealed manneronto the top surface of the lifting base 564. The bellows 562,therefore, maintains reliably the wafer transfer chamber 50 in ahermetically sealed state, thereby allowing the wafer transfer chamber50 to be evacuated. Also, since the movement of the support bar 563 forsupporting the wafer-transfer vacuum robot 60 is isolated from themaintenance of hermetic seal, the support bar 563 moves smoothly andreliably.

Further, since an end of the support bar 563 for supporting thewafer-transfer vacuum robot 60 is fixed onto the upper end portion ofthe driving unit container 61 of the wafer-transfer vacuum robot 60, theheight of the wafer transfer chamber 50 can be reduced, and accordinglythe height of the entire semiconductor wafer processing apparatus 1 canbe reduced.

The entire semiconductor wafer processing apparatus 1 is accommodated ina housing 900. A filter (not shown) and a fan (not shown) are disposedon the ceiling of the housing 900 corresponding to the front section 100so as to produce a downflow into the housing 900. Cassette shelves 11for mounting the cassettes 10 thereon are disposed within and attachedto the housing 900. The cassette shelves 11 are disposed substantiallyopposite to the wafer transfer chamber 50 with respect to theintermediate wafer holding chamber 30. Three cassette shelves 11 arearranged in each of horizontal planes located at two different positionsin the vertical direction. That is, a first set of three cassetteshelves 11 are arranged at the same height, and a second set of threecassette shelves 11 are disposed above the first set of cassette shelves11. As a result of providing the cassette shelves 11 within the housing900, the surfaces of wafers 5 carried in the cassette 10 can bemaintained clean. Also, since a plurality of cassettes 11 are provided,cassettes 11 can be arranged for each of a plurality of kinds ofprocessing. Moreover, it is possible to dispose a cassette which holdswafers for monitoring and a cassette which holds dummy wafers.

A cassette IN/OUT opening 13 is provided at the lower portion of thefront panel 901 of the housing 900. A cassette stage 12 is disposedwithin the housing 900 at the substantially same height as that of thecassette IN/OUT opening 13. The cassette 10 carried into the housing 900through the cassette IN/OUT opening 13 is temporarily held on thecassette stage 12, and also the cassette 10 which contains the processedwafers 5 is temporarily held on the cassette stage 12 before it isdelivered out from the housing 900.

The cassette stage 12 is located under the cassette shelves 11 so as toprevent the wafers 5 contained in the cassette 10 placed on the cassetteshelf 11 from being affected by particles which enter the housing 900from outside through the cassette IN/OUT opening 13 when the cassette 10enters/leaves the housing 900.

Between the intermediate wafer holding chamber 30 and the cassetteshelves 11 is disposed the cassette transfer and wafer transfer device20 which can load the cassette 10 onto and unload from the cassetteshelf 11 and which can transfer wafers 5 between the cassette 10 and theintermediate wafer holding chamber 30. The cassette transfer and wafertransfer device 20 has a ball screw composed of a screw shaft 29 and anut (not shown). As the screw shaft 29 rotates, the cassette transferand wafer transfer device 20 goes up and down accordingly. Since thecassette transfer and wafer transfer device 20 is provided within thehousing 900, the surfaces of wafers 5 being transferred thereby can bemaintained clean.

FIG. 7 is a schematic perspective view for explaining the cassettetransfer and wafer transfer device 20.

A cassette transfer device 21 and a wafer transfer device 23 aredisposed on bases 25 and 26 and can independently perform paralleldisplacement in the direction of a corresponding arrow. The cassettetransfer device 21 has a cassette transfer arm 22 and transfers thecassette 10 which is mounted on a cassette holder 27 attached to an endof the cassette transfer arm 22. The wafer transfer device 23 has aplurality of tweezers 24, each carrying wafers 5 by mounting wafers 5thereon.

FIG. 8A is a side view for explaining the pitch changing mechanism ofthe cassette transfer and wafer transfer device, and FIG. 8B is a rearview taken along the line Y--Y in FIG. 8A.

In the present embodiment, the wafer transfer device 23 has fivetweezers 241-245. The tweezer 241 is integral with a block 260. Nuts232, 233, 234, and 235 are fixed to the tweezers 242, 243, 244 and 245,respectively. The nuts 232 and 234 are in screw-engagement with a screwshaft 210, thereby forming ball screws, respectively. The nuts 233 and235 are in screw-engagement with a screw shaft 211, thereby forming ballscrews, respectively. The upper ends of the screw shafts 210 and 211 areconnected to a motor 220 via an unillustrated gear mechanism. The lowerends of the screw shafts 210 and 211 are rotatably supported by theblock 250. Between the block 250 and the block 260 is disposed a nut270, which is in screw-engagement with a screw shaft 280. The nut 270and the screw shaft 280 constitute a ball screw. When the screw shaft280 is rotated, the nut 27 moves in a horizontal direction accordinglyso as to move the tweezers 241-245 rightward and leftward in FIG. 8A.

A thread of a certain pitch is formed in an area 212 of the screw shaft210 in which the nut 232 is engaged with the screw shaft 210, while athread having a pitch double the pitch in the area 212 is formed in anarea 213 of the screw shaft 211 in which the nut 233 is engaged with thescrew shaft 211. A thread having a pitch three times the pitch in thearea 212 is formed in an area 214 of the screw shaft 210 in which thenut 234 is engaged with the screw shaft 210, while a thread having apitch four times the pitch in the area 212 is formed in an area 215 ofthe screw shaft 211 in which the nut 235 is engaged with the screw shaft211. No relative movement in the vertical direction occurs between theblocks 250 and 260. When the screw shafts 210 and 211 are rotated by themotor 220, the nut 232 is raised by a predetermined distance relative tothe blocks 250 and 260, which are stationary. Further, the nut 233 israised over a distance double the distance over which the nut 232 israised, the nut 234 is raised over a distance three times the distanceover which the nut 232 is raised, and the nut 235 is raised over adistance four times the distance over which the nut 232 is raised. As aresult, the tweezer 241 is not raised, the tweezer 242 is raised over apredetermined distance, the tweezer 243 is raised over a distance doublethe raised distance of the tweezer 242, the tweezer 244 is raised over adistance three times the raised distance of the tweezer 242, and thetweezer 245 is raised over a distance four times the raised distance ofthe tweezer 242. As a result, the pitch of the tweezers 241-245 can bechanged uniformly.

FIG. 9 is a schematic cross-sectional view for explaining the operationof transferring wafers 5 in the semiconductor processing apparatus 1according to the first embodiment. The operation for transferring andprocessing wafers 5 will be described with reference to FIGS. 3-9.

The cassette 10 which has been carried into the housing 900 of thesemiconductor wafer processing device 1 through the cassette IN/OUTopening 13 is first placed on the cassette stage 12. Then, the cassette10 is transferred onto the cassette holder 27 attached to the end of thecassette transfer arm 22 of the cassette transfer and wafer transferdevice 20. The cassette transfer and wafer transfer device 20 carriesthe cassette 10 to the upper portion of the housing 900 and thentransfers it onto the cassette shelf 11. Next, the cassette transferdevice 21 moves leftward, and the wafer transfer device 23 then movesrightward so that the wafers 5 in the cassette 10 are mounted onto thetweezers 24. At this time, the pitch of the tweezers 24 is set to beequal to the pitch of the grooves of the cassette 10.

Subsequently, the wafer transfer device 23 is retracted and rotated by180 degrees. Next, the pitch of the tweezers 24 is changed such that thepitch of the tweezers 24 becomes equal to the pitch of the wafersupporting grooves 45 of the wafer holder 40. Subsequently, the tweezers24 are moved leftward so as to load wafers 5 into wafer holder 40 withinthe intermediate wafer holding chamber 30. In the present embodiment,five wafers 5 are transferred at once from the cassettes 10 to the waferholder 40 by the cassette transfer and wafer transfer device 20. Whenthe wafers 5 are transferred into the intermediate wafer holding chamber30 by the cassette transfer and wafer transfer device 20, the gate valve92 is closed, while the front door valve 91 is opened.

After the wafer holder 40 in the intermediate wafer holding chamber 30is loaded with the wafers 5, the front door valve 91 is closed, and theintermediate wafer holding chamber 30 is evacuated.

After the evacuation, the gate valve 92 is opened. The wafer transferchamber 50 has been evacuated in advance.

Subsequently, the wafers 5 are held by the wafer mounting arms 68 of thewafer-transfer vacuum robot 60 in the evacuated wafer transfer chamber50, and are transferred from the wafer holder 40 within the intermediatewafer holding chamber 30 to the wafer boat 75 within the reactionchamber 70. At this time, the gate value 93 is open, and the reactionchamber 70 has already been evacuated. Since the pitch of the wafersupporting grooves 45 of the wafer holder 40 is equal to the pitch ofthe wafers 5 loaded on the wafer boat 75, the pitch of the wafermounting arms 68 of the wafer-transfer vacuum robot 60 is not changedand is maintained constant. In the present embodiment, two wafers aretransferred at a time from the wafer holder 40 to the wafer boat 75 bythe wafer-transfer vacuum robot 60.

After the transfer operation, the gate valve 93 is closed, and apredetermined atmosphere is created in the reaction chamber 70.Subsequently, the two wafers 5 loaded onto the wafer boat 75 in thereaction chamber 70 are simultaneously subjected to a predeterminedprocessing such as film forming processing.

Upon completion of the predetermined processing, the reaction chamber 70is evacuated, and the gate valve 93 is opened. The wafers 5 aretransferred to the wafer holder 40 within the evacuated intermediatewafer holding chamber 30 by the wafer-transfer vacuum robot 60. At thistime, the pitch of the wafer carrying arms 68 of the wafer-transfervacuum robot 60 is not changed and is maintained constant. Two wafersare transferred at a time.

Subsequently, the gate valve 92 is closed, and atmospheric pressure iscreated in the intermediate wafer holding chamber 30 using nitride orthe like, and the wafers 5 are cooled until the temperature of eachwafer reaches a predetermined temperature.

Subsequently, the front door valve 91 is opened, and the wafers 5 aretransferred into the cassette 10 by the wafer transfer device 23 of thecassette transfer and wafer transfer device 20. At this time, the pitchof the tweezers 24 is changed from a pitch corresponding to the pitch ofthe wafer supporting grooves 45 of the wafer holder 40 to a pitchcorresponding to the pitch of the grooves of the cassette 10.

When a predetermined number of wafers 5 are transferred into thecassette 10, the cassette 10 is transferred to the cassette stage 12 bythe cassette transfer device 21. The cassette 10 is then taken outthrough the cassette IN/OUT opening 13.

As described above, since two wafers are simultaneously treated in thereaction chamber 70, wafers can be processed with an improvedefficiency. Since the pitch of the wafer supporting grooves 45 of thewafer holder 40 is equal to the pitch of wafers held on the wafer boat75, it is not necessary to change the pitch of wafer mounting arms 68 ofthe wafer-transfer vacuum robot 60. Therefore, the structure of thewafer-transfer vacuum robot 60 can be simplified and the vacuum createdin the wafer transfer chamber 50 is prevented from being contaminated.Since two wafers 5 can be transferred at a time, the efficiency of wafertransfer can be increased.

Although the pitch of wafers 5 is changed by the cassette transfer andwafer transfer device 20, the cassette transfer and wafer transferdevice 20 is used under the atmospheric pressure. Therefore, even whenthe pitch of wafers 5 is changed, the cassette transfer and wafertransfer device 20 can have a simpler structure and can be manufacturedat lower cost compared to the case in which the pitch of wafers 5 ischanged in a vacuum. In addition, the generation of particles can besuppressed.

As described above, the pitch of wafers 5 is changed under theatmospheric pressure and is fixed under the reduced pressure, and aplurality of wafers 5 are transferred at a time. Therefore, themanufacturing cost of the transfer apparatus can be decreased, and thesize of the transfer apparatus is prevented from increasing. Inaddition, the generation of particles is suppressed, so that wafers 5can be transferred in a clean environment. Moreover, simultaneoustransfer of a plurality of wafers 5 improves the throughput, and thecapability of changing the pitch of wafers 5 makes it possible to changethe pitch of wafers 5 so as to guarantee that wafer processing isperformed highly accurately in the reaction chamber 70.

In the present embodiment, the walls 53 and 54 of the wafer transferchamber 50 are opposed to each other so as to arrange on a substantiallystraight line the reaction chamber 70, the wafer transfer chamber 50,and the intermediate wafer holding chamber 30, and the wafer transferchamber 50 has a rectangular shape as viewed from above. As the wafertransfer chamber 50 has a rectangular shape, the size of the wafertransfer chamber 50 can be reduced, and the area occupied by the wafertransfer chamber 50 can be reduced accordingly. Thus, the semiconductorwafer processing apparatus 1 occupies less area within a clean room. Byadopting the rectangular shape, the cost of manufacture of the wafertransfer chamber 50 is reduced, and a required maintenance space is alsoreduced. Further, the distance over which a connection is made betweenthe wafer transfer chamber 50 and another wafer transfer chamber or thelike can be reduced. This allows the wafers 5 to be readily transferredbetween the wafer transfer chamber 50 and another wafer transfer chamberor the like without providing a wafer transfer device at a connectingsection therebetween; thus the semiconductor wafer processing apparatus1 can accordingly be made simpler in structure and manufactured at lowercost. A plurality of semiconductor wafer processing units, each havingthe structure such that the reaction chamber 70, the wafer transferchamber 50, and the intermediate wafer holding chamber 30 are arrangedon a substantially straight line, can be readily arranged in parallel sothat they occupy less area.

Second Embodiment

FIG. 10 is a cross-sectional view for explaining a semiconductor waferprocessing apparatus according to a second embodiment of the presentinvention. The semiconductor wafer processing apparatus 1 of the presentembodiment is the same as that of the first embodiment except that: thereactions chambers 70, the wafer transfer chamber 50, and theintermediate wafer holding chambers 30 are located at the lower portionof the housing 900; and the wafer-transfer vacuum robot 60, and thescrew shaft 561 and the like for lifting/lowering the wafer-transfervacuum robot 60 are located at the upper portion of the housing 900.

Third Embodiment

FIG. 11 is a cross-sectional view for explaining a semiconductor waferprocessing apparatus according to a third embodiment of the presentinvention.

According to the present embodiment, six reaction chambers 70 arearranged in the vertical direction on the wall 53 of the wafer transferchamber 50, and four intermediate wafer holding chambers 30 are arrangedin the vertical direction on the wall 54 of the wafer transfer chamber50. Because of an increase in the number of the reaction chambers 70 aswell as the intermediate wafer holding chambers 30, the height of thewafer chamber 50 is increased accordingly. In order to accommodate thismany reaction chambers 70 and intermediate wafer holding chambers 30within the housing 900, the projecting section 52 of the wafer transferchamber 50, the screw shaft 561, the bellows 562, and the support bar563 for supporting the wafer-transfer vacuum robot 60 are partiallyprojected from the housing 900. Since these projecting portions can beprojected downward from the floor of a clean room, the height of thewafer transfer chamber 50 can be increased, thereby allowing morereaction chambers 70 as well as more intermediate wafer holding chambers30 to be arranged in the vertical direction. Thus, more wafers 5 can beprocessed within less area.

Fourth Embodiment

FIG. 12 is a plan view for explaining a semiconductor wafer processingapparatus according to a fourth embodiment of the present invention.

In the present embodiment, semiconductor wafer processing units 2 and 2'are disposed in parallel, the unit 2 (2') having the structure such thatthe reaction chamber 70 (70'), the wafer transfer chamber 50 (50'), theintermediate wafer holding chamber 30 (30'), the cassette transfer andwafer transfer device 20 (20'), and the cassette shelf 10 (10') arearranged on a substantially straight line. The semiconductor waferprocessing units 2 and 2' each having such a structure can be readilydisposed in parallel, thereby reducing the area occupied by the entireapparatus composed of the units 2 and 2'.

The wafer transfer chamber 50 (50') has a rectangular shape as viewedfrom above. Accordingly, the distance over which a connection is madebetween the wafer transfer chamber 50 and the wafer transfer chamber 50'can be reduced. This allows a wafer to be readily transferred betweenthe wafer transfer chamber 50 and the wafer transfer chamber 50' withoutproviding a wafer transfer device in an intermediate wafer transferchamber 90, which serves as a connecting section between the chambers 50and 50'. Thus, the semiconductor wafer processing apparatus 1 canaccordingly be made simpler in structure and manufactured at lower cost.The intermediate wafer holding chamber 90 can also be used as a coolingchamber for cooling a wafer or as a preheating chamber for preheating awafer.

A space located between the reaction chamber 70 and the reaction chamber70' is large enough for use as a common maintenance space 3 for thesemiconductor wafer processing units 2 and 2'.

Fifth Embodiment

FIG. 13 is a plan view for explaining a semiconductor wafer processingapparatus according to a fifth embodiment of the present invention.

In the present embodiment, a semiconductor wafer processing unit 6according to the present invention, which has the structure such thatthe reaction chamber 70, the wafer transfer chamber 50, the intermediatewafer holding chamber 30, the cassette transfer and wafer transferdevice 20, and the cassette shelf 10 are arranged on a substantiallystraight line, is connected to a semiconductor wafer processing unit 7,which includes a wafer transfer chamber 150 which is hexagon-shaped asviewed from above and on side walls of which cassette chambers 131 and132, reaction chambers 171 and 172, and a wafer cooling chamber 142 areprovided.

Since the wafer transfer chamber 50 is rectangle-shaped, it can bereadily connected via the wall 51 thereof to a semiconductor waferprocessing unit having a different shape.

Also, in the present embodiment, the distance over which a connection ismade between the wafer transfer chamber 50 and the wafer transferchamber 150 can be reduced. This allows a wafer to be readilytransferred between the wafer transfer chamber 50 and the wafer transferchamber 150 without providing a wafer transfer device in an intermediatewafer transfer chamber 90, which serves as a connecting section betweenthe chambers 50 and 150. Thus, the semiconductor wafer processingapparatus as a whole can accordingly be made simpler in structure andmanufactured at lower cost. The intermediate wafer transfer chamber 90can also be used as a cooling chamber for cooling a wafer or as apreheating chamber for preheating a wafer.

Sixth Embodiment

FIG. 14 is a plan view for explaining a semiconductor wafer processingapparatus according to a sixth embodiment of the present invention.

In the present embodiment, a wafer transfer chamber 55 is octagon-shapedas viewed from above, and the reaction chambers 70 are provided inlayers on each of the seven side walls of the wafer transfer chamber 55.

Seventh Embodiment

FIG. 15 is a plan view for explaining a semiconductor wafer processingapparatus according to a seventh embodiment of the present invention.

In the present embodiment, the wafer transfer chamber 55 of FIG. 14 fromwhich reaction chambers 70a are removed is connected via an intermediatewafer transfer chamber 90 to the wafer transfer chamber 55 of FIG. 14from which reaction chambers 70b are removed. The intermediate wafertransfer chamber 90 can also be used as a cooling chamber for cooling awafer or as a preheating chamber for preheating a wafer.

What is claimed is:
 1. A substrate processing apparatus, comprising:asubstrate transfer chamber which can be depressurized; a substrateprocessing chamber, disposed on a first side wall of said substratetransfer chamber, for processing a substrate; an intermediate substrateholding chamber which is disposed on a second side wall of saidsubstrate transfer chamber and which can be depressurized independentlyof said substrate transfer chamber; a first substrate holding device,disposed within said intermediate substrate holding chamber, for holdingsaid substrate; a second substrate holding device, disposed within saidsubstrate processing chamber, for holding said substrate; a firstsubstrate transfer device disposed within said substrate transferchamber, said first substrate transfer device being capable oftransferring said substrate between said substrate processing chamberand said intermediate substrate holding chamber; a first valve disposedbetween said substrate processing chamber and said substrate transferchamber, said first valve being capable of providing hermetic vacuumisolation between said substrate processing chamber and said substratetransfer chamber when closed and allowing said substrate to passtherethrough when opened; a second valve disposed between said substratetransfer chamber and said intermediate substrate holding chamber, saidsecond valve being capable of providing hermetic vacuum isolationbetween said substrate transfer chamber and said intermediate substrateholding chamber when closed and allowing said substrate to passtherethrough when opened; an atmospheric pressure section located at aside which is different from the substrate transfer chamber's side withrespect to said intermediate substrate holding chamber; a third valvedisposed between said intermediate substrate holding chamber and saidatmospheric pressure section, said third valve being capable ofmaintaining said intermediate substrate holding chamber under vacuum inisolation from said atmospheric pressure section when closed andallowing said substrate to pass therethrough when opened; a cassetteholding device disposed within said atmospheric pressure section; and asecond substrate transfer device disposed within said atmosphericpressure section, said second substrate transfer device being capable oftransferring said substrate between a cassette held in said cassetteholding device and said intermediate substrate holding chamber; whereinsaid second substrate holding device is capable of holding a pluralityof substrates, said first substrate holding device is capable of holdinga plurality of substrates, and the pitch of substrates held by saidfirst substrate holding device is substantially identical to that ofsubstrates held by said second substrate holding device.
 2. A substrateprocessing apparatus as recited in claim 1, wherein said first substratetransfer device is capable of transferring a plurality of substrates atone time under reduced pressure.
 3. A substrate processing apparatus asrecited in claim 1, wherein said second substrate transfer device iscapable of transferring a plurality of substrates at one time andchanging the pitch of said substrates.
 4. A substrate processingapparatus comprising:a substrate transfer chamber which can bedepressurized; a plurality of substrate processing chambers, disposed ona first side wall of said substrate transfer chamber and stacked in avertical direction, each for processing a substrate; a plurality ofintermediate substrate holding chambers which are disposed on a secondside wall of said substrate transfer chamber and stacked in a verticaldirection and which can be depressurized independently of said substratetransfer chamber; a plurality of first substrate holding devices,respectively disposed within said intermediate substrate holdingchambers, each for holding said substrate; a plurality of secondsubstrate holding devices, respectively disposed within said substrateprocessing chambers, each for holding said substrate; a first substratetransfer device disposed within said substrate transfer chamber, saidfirst substrate transfer device being capable of transferring saidsubstrate between said substrate processing chambers and saidintermediate substrate holding chambers; a plurality of first valvesrespectively disposed between said substrate processing chambers andsaid substrate transfer chamber, each of said first valves being capableof providing hermetic vacuum isolation between each of said substrateprocessing chamber and said substrate transfer chamber when closed andallowing said substrate to pass therethrough when opened; a plurality ofsecond valves respectively disposed between said substrate transferchamber and said intermediate substrate holding chambers, each of saidsecond valves being capable of providing hermetic vacuum isolationbetween said substrate transfer chamber and each of said intermediatesubstrate holding chambers when closed and allowing said substrate topass therethrough when opened; an atmospheric pressure section locatedat a side which is different from the substrate transfer chamber's sidewith respect to said intermediate substrate holding chambers; aplurality of third valves respectively disposed between saidintermediate substrate holding chambers and said atmospheric pressuresection, each of said third valves being capable of maintaining each ofsaid intermediate substrate holding chambers under vacuum in isolationfrom said atmospheric pressure section when closed and allowing saidsubstrate to pass therethrough when opened; a cassette holding devicedisposed within said atmospheric pressure section; and a secondsubstrate transfer device disposed within said atmospheric pressuresection, said second substrate transfer device being capable oftransferring said substrate between a cassette held in said cassetteholding device and said intermediate substrate holding chambers; whereinsaid first and second side walls of said substrate transfer chamber areopposed to each other so as to arrange on a substantially straight lineall of said substrate processing chambers, said substrate transferchamber, and all of said intermediate substrate holding chambers.
 5. Asubstrate processing apparatus as recited in claim 4, wherein saidsubstrate transfer chamber has a rectangular shape as viewed from above.6. A substrate processing apparatus as recited in claim 4, wherein saidcassette holding device is located opposite to said substrate transferchamber with respect to said intermediate substrate holding chambers. 7.A substrate processing apparatus as recited in claim 4, wherein thereare provided a plurality of substrate processing units, each comprisingsaid substrate processing chambers, said substrate transfer chamber,said first substrate transfer device, and said intermediate substrateholding chambers; andsaid plurality of substrate processing units areinterconnected via a second intermediate substrate transfer chamberdisposed between adjacent substrate transfer chambers.
 8. A substrateprocessing apparatus as recited in claim 7, wherein said substratetransfer chamber has a rectangular shape as viewed from above, and saidplurality of substrate processing units are connected via said secondintermediate substrate transfer chamber disposed between said adjacentsubstrate transfer chambers.
 9. A substrate processing apparatus,comprising:a substrate transfer chamber which can be depressurized; asubstrate processing chamber, disposed on a first side wall of saidsubstrate transfer chamber, for processing a substrate; an intermediatesubstrate holding chamber which is disposed on a second side wall ofsaid substrate transfer chamber and which can be depressurizedindependently of said substrate transfer chamber; a first substrateholding device, disposed within said intermediate substrate holdingchamber, for holding said substrate; a second substrate holding device,disposed within said substrate processing chamber, for holding saidsubstrate; a first substrate transfer device disposed within saidsubstrate transfer chamber, said first substrate transfer device beingcapable of transferring said substrate between said substrate processingchamber and said intermediate substrate holding chamber; a first valvedisposed between said substrate processing chamber and said substratetransfer chamber, said first valve being capable of providing hermeticvacuum isolation between said substrate processing chamber and saidsubstrate transfer chamber when closed and allowing said substrate topass therethrough when opened; a second valve disposed between saidsubstrate transfer chamber and said intermediate substrate holdingchamber, said second valve being capable of providing hermetic vacuumisolation between said substrate transfer chamber and said intermediatesubstrate holding chamber when closed and allowing said substrate topass therethrough when opened; an atmospheric pressure section locatedat a side which is different from the substrate transfer chamber's sidewith respect to said intermediate substrate holding chamber; a thirdvalve disposed between said intermediate substrate holding chamber andsaid atmospheric pressure section, said third valve being capable ofmaintaining said intermediate substrate holding chamber under vacuum inisolation from said atmospheric pressure section when closed andallowing said substrate to pass therethrough when opened; a cassetteholding device disposed within said atmospheric pressure section; and asecond substrate transfer device disposed within said atmosphericpressure section, said second substrate transfer device being capable oftransferring said substrate between a cassette held in said cassetteholding device and said intermediate substrate holding chamber; whereinsaid second substrate transfer device is disposed between saidintermediate substrate holding chamber and said cassette holding device,and said second substrate transfer device is a cassette transfer andsubstrate transfer device capable of transferring said substrate betweenthe cassette held by said cassette holding device and said intermediatesubstrate holding chamber, as well as capable of transferring thecassette to and from said cassette holding device.
 10. A substrateprocessing apparatus, comprising:a substrate transfer chamber; aplurality of substrate processing chambers disposed on a side wall ofsaid substrate transfer chamber, said plurality of substrate processingchambers being stacked in the vertical direction and being separatedfrom one another to form spaces respectively between adjacent saidsubstrate processing chambers and being disposed outside said substratetransfer chamber under a different vacuum or pressure than the substratetransfer chamber.
 11. A substrate processing apparatus as recited inclaim 10, wherein said substrate transfer chamber is a chamber fortransferring a substrate under a vacuum condition.
 12. A substrateprocessing apparatus as recited claim 11, further comprises a pluralityof gate valves respectively disposed between said plurality of substrateprocessing chambers and said substrate transfer chamber.
 13. A substrateprocessing apparatus as recited in claim 10, further comprising aplurality of substrate holding chambers disposed on a second side wallof said substrate transfer chamber, said plurality of substrate holdingchambers being stacked in the vertical direction and being separated byone another to form spaces respectively between adjacent said substrateprocessing chambers; anda plurality of second gate valves respectivelydisposed between said plurality of substrate holding chambers and saidsubstrate transfer chamber.
 14. A substrate processing apparatus,comprising:a substrate transfer chamber; a plurality of substrateprocessing chambers disposed on a side wall of said substrate transferchamber, said plurality of substrate processing chambers being stackedin the vertical direction, being separated from one another to formspaces respectively between adjacent ones of said substrate processingchambers and being disposed outside said substrate transfer chamber.